SavedObjectsTypeMappingDefinition should support the dynamic option

[joshdover]

We should allow the new saved objects mappings API added in (#57430) to utilize the dynamic option in order to have fields that are not indexed by Elasticsearch.

This should probably only be allowed to be false | 'strict' so we don't introduce unexpected index fields.

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[pgayvallet]

Example of type using it: x-pack/legacy/plugins/canvas/server/mappings.ts

kibana/x-pack/legacy/plugins/canvas/server/mappings.ts

Lines 10 to 25 in 7ac8e4d

	export const mappings = {
	[CANVAS_TYPE]: {
	dynamic: false,
	properties: {
	name: {
	type: 'text',
	fields: {
	keyword: {
	type: 'keyword',
	},
	},
	},
	'@timestamp': { type: 'date' },
	'@created': { type: 'date' },
	},
	},